In the past a number of devices have been developed for causing a telephone call on a user's incoming telephone line to be automatically diverted to a different designated telephone line. This diversion of incoming telephone calls is commonly called "call forwarding". The telephone company provides the call forwarding service as one of several auxiliary services that are provided for customers.
In addition, various telephone inline switching devices have been developed for diverting and rerouting incoming telephone calls automatically. It is common practice for most of these devices to utilize a two-line system whereby as a telephone call is received on one line it is automatically diverted out to a preprogrammed telephone number on the second line.
The telephone company service which is provided under call forwarding is a service that allows the customer/user to access the system by dialing a code on his telephone instrument such as 72#. This code number accesses the call forwarding system and the telephone number to which the incoming calls are to be diverted is then dialed into the system usually by use of a touchtone or DTMF keypad. If the remote designated telephone instrument is answered, the connection is automatically completed. However, on the other hand if there is no answer at the remote instrument or if the line is busy, the user must then hang up and dial a second time to complete the call forwarding program.
Under normal conditions the customer/user, if he wants to cancel the call forwarding service, must return to his original telephone station and dial a second code such as 73# to cancel the preprogrammed call forwarding service. After cancellation the telephone line can be used in the normal way or a new call forwarding telephone number can be programmed by repeating the above cycle.
Since the use of the call forwarding service provided through the telephone company has been found to be the most economical and expeditious, most of the prior art devices up to this point have been directed to providing some method of remotely changing or reprogramming the call forwarding telephone number in the telephone company equipment without having to return to the original telephone station. Although some of these methods have been marketed, they have not proven to be as efficient or have the ease of operation that is necessary to make a system or a device of this nature economically practical.
An example of a prior art system is the arrangement whereby two or more calls to the original telephone number are required within a specified time interval. Once the proper number of calls has been received within the time required the device automatically initiates and dials a cancellation of the call forwarding function. After this has been accomplished the person may call his original telephone number again and after providing the required code number can reprogram his device with a new remote telephone number. After the reprogramming is complete the device will automatically seize the telephone line and establish the new call forwarding number once the user has disconnected from the line. This arrangement is rather cumbersome due to the fact that a plurality of telephone calls must be initiated to the original telephone number in order for the machine to properly sense the requirement that the call forwarding function must be terminated in order for the use to regain control over the call forwarding function up until now, this is the only way that has been possible to recapture control of the device in order to reprogram the call forwarding service from a remote location. It is also noted that these calls can be made from any remote location in the telephone system which allows the remote programming to be actuated by an unauthorized individual having access to the required code or the call forwarding service can be accidentally terminated by two or more calls being received coincidentally within a short time period from an innocent third-party.